The findings from two large studies, presented at a Europeanneurology meeting in Stockholm on Tuesday, followed thecompanies' announcement last month that they were scrappinglarge-scale clinical trials of the drug after it failed toimprove memory or thinking skills in patients with mild tomoderate Alzheimer's.

Many researchers had expected bapineuzumab to fail this testbecause they believe that Alzheimer's starts years before memoryproblems become apparent, and that treatment when patientsalready have dementia may be too late.

But they have been eagerly awaiting the so-called biomarkerresults, which measure fluids and tissues in the body, to see ifthe drug hit its biological targets and therefore, could work atan earlier stage of the disease.

The biomarker results show that bapineuzumab significantlyreduced levels of the protein beta amyloid on the brain scans ofpatients with a gene mutation that increases their risk ofAlzheimer's, compared with subjects who were give a placebo.

The drug also significantly reduced the amount of a toxicform of the protein tau in spinal fluid, a sign of brain celldeath, compared with patients who were given a placebo.

However, MRI tests showed patients in the treatment andplacebo groups had a similar loss of brain volume.

Dr. Reisa Sperling of Harvard Medical School and Brigham andWomen's Hospital presented results of a study of patients whocarry the ApoE4 gene mutation. She said the findings were not a"home run in biomarkers," but are encouraging.

"I am happy there is evidence that we are having some effecton the disease process in the brain," she said in a telephoneinterview from Stockholm.

"I am very interested in moving towards a much earlier stageof Alzheimer's disease in which we might be able to impact thebiology at a time when we might prevent symptoms."

The results of a second trial of patients who were notcarriers of the ApoE4 mutation, presented by Dr. StephenSalloway of Brown University in Rhode Island, showed nosignificant improvements, but there was some reduction in amarker of brain cell death at the highest dose. Because thefollow-up study only included 39 patients, however, it waslikely too small to show much of an effect, Salloway said.

In both trials, a significant number of patients experienceda brain-swelling side effect known as vasogenic edema, and ratesof this problem increased as the dose of the drug increased.

In 2009, the highest dose of the drug was dropped from thenon-carrier study because of this brain-swelling issue.

Researchers said the lower doses tested in the studies -- 0.5 milligram per kilogram in the ApoE4 carriers and both 0.5mg/kg and 1.0 mg/kg in the non-carriers -- may explain why thepatients failed to see a benefit in memory and thinking skills.

'POSITIVE DIRECTION'

Maria Carrillo of the Alzheimer's Association, who had seenthe results, said they suggest the biomarkers were moving in a"positive direction."

Sanford C. Bernstein analyst Tim Anderson said in a note toclients the results "leave open the possibility" that thebapineuzumab may work in earlier stage disease.

Researchers will be comparing these findings to those of Eli Lilly and Co's similar drug, solanezumab. Althoughthe Lilly drug also failed to meet its study's main goals inmild to moderate patients, the company did see a slight benefitwhen they isolated results for mild patients.

Biomarker results for Lilly's drug are expected to bereleased on Oct. 8 at a neurology meeting in Boston. Researchershave not yet analyzed pooled data on mild patients in thebapineuzumab studies.

Although Pfizer and J&J discontinued all studies involvingthe intravenous form of bapineuzumab, they have an ongoing studytesting the treatment in a shot form.

Dr. Eric Yuen of J&J said the newer formulation may offer amore smooth exposure to the drug than the IV version, whichcould help reduce some of the side effects.

Sperling said side effects will play a role in the future ofbapineuzumab. "I think it will be important to see whether wewill get a better side effect profile that will allow us to dosehigher," Sperling said.

Several studies, including one proposed by Sperling, will betesting drugs such as bapineuzumab in patients with normalmemories who are likely to develop Alzheimer's, either becausethey are genetically predisposed to it or because biomarkertests suggest it is already forming.

Salloway, who is also helping to organize a study known asDIAN in patients with an inherited form of the disease, saidresearchers will examine all available data in order to pickcompounds likely to influence the disease process early on.